Various perpetual calendars have been developed in the past. However, those of which applicant is aware are of the type that require the use of magnetic material to either accomplish the movement of plates to register with calendar indicia or include magnetic rings that are physically moved on the surface of the calendar to surround a particular day.
In any of the foregoing type the inclusion of magnetic material usually greatly increases the cost of the calendar because of the cost of the material as well as the additional labor to inserting the magnetic material.
Further, with some magnetic calendars there are separate magnets such as bars or horseshoe magnets which are not attached to the calendar and if lost or misplaced render the calendar inoperative until replaced.